Objective To explore the effect of physical exercise on semen quality in order to provide basic data and theoretical basis for the improvement of male reproductive health.Methods A cross-sectional study was conducted on 1 059 males who visited the Reproductive Medicine Center of Shandong Maternal and Child Health Hospital for medical treatment and physical examination during July 2022 and April 2023.Their demographic data and physical exercise data were surveyed with questionnaires.Total sperm count,sperm concentration,total sperm motility,forward movement and normal sperm morphology were analyzed with computer aided analysis.Logistic regression model and multiple linear regression model were applied to analyze the effects of physical exercise on semen quality.Results After adjustment for confounding factors such as age,body mass index,alcohol consumption and smoking,logistic regression analysis showed that the risk of abnormal semen quality was increased in patients with moderate and heavy exercise intensity(OR=2.103,OR=2.229).Compared with the participants with physical exercise ≤10 min per session,those with＞20 min per session had a lower risk of abnormal semen quality(OR=0.357,0.256,0.289 for exercise time for＞20～30,＞30～60,＞60 min,respectively).There was no statistical significance between physical exercise frequency and semen quality(P＞0.05).The participants having exercise well were at a lower risk for abnormal semen quality(OR=0.711).Multiple linear regression analysis revealed that the frequency of physical exercise was an influencing factor of sperm concentration(β=7.474,95％CI:4.800～10.149,P＜0.05);the time of physical exercise per session was an influencing factor for total sperm count(β=20.632,95％CI:7.634～33.629);the intensity of physical exercise(β=-1.461,95％CI:-2.392～-0.530)and time of physical exercise per session(β=2.608,95％CI:1.404～3.812,P＜0.05)were influencing factors for percentage of forward motility sperm(P＜0.05);and physical exercise intensity(β=-1.934,95％CI:-3.238～-0.630),time of physical exercise per session(β=4.211,95％CI:2.525～5.897)and frequency of physical exercise(β=-2.008,95％CI:-3.480～-0.536)were influencing factors of total sperm motility(P＜0.05).Conclusion Physical exercise may affect semen quality,greater intensity of physical exercise may be a risk factor for abnormal semen quality,and longer physical exercise time may be related to improving semen quality.Therefore,proper physical exercise can help improve semen quality.